In a typical medication packing machine, each distributed medication is packaged in a heat-fusible packing sheet using a sealing device.
Various sealing devices of the above type for use with tablet medication packing machines have been known. For example, Japanese Patent Laid-Open No. 8-230832 discloses a sealing device capable of freely changing the size of packing bags. In addition, Japanese Patent Laid-Open No. 9-202301 discloses a sealing device capable of changing the size of packing bags according to the volume of tablets to be packed.
Such sealing devices, however, have some problems. First, determination of the size of the packing bag based on a calculation result of the volume of a tablet inevitably requires volume data for each tablet. It is therefore difficult to put the foregoing prior art devices to practical use. The reason is that there are various types of medications (e.g., tablet, capsule, powder and so on), each type varying in shape and size. For instance, some medications have the form of an ellipse and other medications have the form of a hexagon. Accordingly, enormous volumes of data are required in determining the size of packing bags. Besides, in the case of packing a plurality of tablets or different kinds of medications in each packing bag, it is required to take dead spaces or the like into consideration. Therefore, it is extremely difficult to find the size of the packing bag by performing arithmetic on the basis of only the volume of each medication. For this reason, it becomes necessary to examine packing results to accumulate knowledge of how to set volume information depending on the medication shape, size, and combination, which is very labor-consuming. In addition, in such a method of determining a packing bag's size, it is impossible to make changes, unless the control program is changed. Accordingly, it is impossible to flexibly deal with differences in the type and quantity of medication to be packaged. Furthermore, since the control program itself is stored in read-only memory (ROM), replacement of the control program becomes necessary.
Additionally, after the packing operation, it is necessary to make sure that the type and quantity of medications packaged in individual packing bags is correct. However, if the packing bags are different in bag length between each medication-taking time ("MORNING", "MIDDAY", and "EVENING"), such confirmation of whether the type and quantity of medication packaged is correct or not is difficult to make. In addition, when trying to fold an elongated series of packing bags of different lengths, and to put same into a medication envelop, it is hard to actually fold the series of packing bags because the positions of perforation lines, along which folding can be carried out easily, are not aligned with one another (irregular alignment). This accordingly results in poor workability. If folding is carried out at a wrong position other than a line of perforations, this may cause separation at a wrong position by mistake.